Lighting devices, for street lighting for example, with solid state light radiation sources (for example LED sources) are considered to be competitive because of their efficiency and their lighting performance, for example in terms of high luminosity per watt (lm/W) and because of the possibility of increasing the spacing between the standards on which they are mounted.
Devices intended for specific applications (such as ordinary street lighting and the lighting of highways, pedestrian areas, bicycle paths, etc.) may offer special forms of lighting distribution provided by means of standard structures, in such a way that the same basic components (light radiation sources, mounting boards such as printed circuit boards (PCBs), casings, wiring, etc.) can be used with changes in the associated optical systems, as required by the specific applications.
However, solutions of this type may be limited in their flexibility by the generally small number of different combinations that can be obtained with the same basic components.
These considerations are valid not only for solutions based on refractive optics but also for those based on reflective optics.
In the case of refractive optics, a distributed array of light radiation sources (for example, 8 to 16 LEDs spaced a few centimeters apart) may have an associated “family” of lenses, made of plastic material for example, formed in one piece. Each type of lens provides a specific radiation configuration on the road surface, making it possible to provide different applications by using multiple arrays of multiple lenses.
These solutions are inherently limited in terms of the reliability of the lenses, particularly those made of plastic material, which are to be placed in the proximity of the light radiation sources, and also in terms of the high sensitivity to the configuration of the radiation emission from the source (of the LED type for example), and the possibility of causing a greater amount of dazzle than where reflective optics are used.
Reflective optics may, for example, include the use of a certain number of groups (or “clusters”) of LEDs on a printed circuit board (PCB) coupled to aluminized reflectors which can be made, for example, in different versions. In all cases it may be possible to include additional components so as to provide, for example, a radiation configuration suited to the lighting of pedestrian areas, on the basis of a version used for street lighting. Various solutions may also allow the lighting configuration to be rotated, through 180° for example, by rotating the module inside the lighting device in a corresponding way.
However, solutions of this type may be subject to limitations due, for example, to the fact that the rotation of the reflector may require a corresponding rotation of the board on which the light radiation source is mounted, or may require the provision of board and radiation source assemblies of a different type. Because of all these factors, there are evident limitations in terms of flexibility of use.